Sodium bisulfite (usually shown by formula to be NaHSO.sub.3) has heretofore been used for many commercial purposes, such as a preservative for prevention of the deterioration of liquids such as food stuffs and pharmaceutical solids, and has been used medically externally for parasitic skin diseases and internally as a gastrointestinal antiseptic.
The solid sodium bisulfite of commerce reportedly consist chiefly of sodium metabisulfite, Na.sub.2 S.sub.2 O.sub.5, and sodium bisulfite, and, for purposes of this invention, such is believed to possess the same properties as (and to be equivalent to) sodium bisulfite when dissolved in an aqueous solution.
Anticoagulants and antithrombotics are a group of compounds with diversified pharmacologic actions, used in a variety of chemical thrombotic disorders. Thrombotic disorders are generally divided into venous thromboses and arterial occlusive disorders. Venous thrombsis of the lower extremities is important because it can cause pulmonary embolism which may be fatal. Heparin and warfarin are commonly used in clinical medicine for prevention and treatment of deep venous thrombosis and pulmonary embolism. Their pharmacological actions are in the inhibition of blood coagulation activity (i.e., heparin) or of synthesis of coagulation factors (i.e., warfarin). Platelets play an important part in arterial thrombosis. Drugs that inhibit platelet aggregation are generally regarded as being potentially useful for prophylactic therapy of arterial thrombotic disorders, including, for example, stroke, myocardial infarction and peripheral vascular disease. Despite the availability of many agents which possess anti-platelet aggregating properties, only a few are currently under clinical trials (for example, aspirin, dipyridamole, sulfinpyrazone). None of these agents exhibit unequivocal efficacy. Compounds with more specific pharmacological action are urgently sought in order to provide better medical care for patients with these serious disorders.
An anti-platelet aggregatory agent is a substance which inhibits platelet aggregation.
An antithrombotic agent is a substance which inhibits formation or development of a thrombus (or thrombosis). For present patent purposes, it will be understood that the term "thrombus" or equivalent includes the subject matter of the term "embolus" unless otherwise specifically indicated. In general, an antithrombotic agent may display in the presence of mammalian blood or appropriately prepared plasma anticoagulant activity and/or anti-platelet aggregatory activity.